Some thoughts on string tension

Like many people, I had always wondered why lute strings look so thin in old paintings. Was it because the artist couldn’t be bothered with showing the details of the strings, or was it because the thickest strings were not as thick as we might expect? We know that lutes were strung with sheep gut (and we have no reason to believe that the density of gut was significantly different in the past), but to achieve the kind of string tensions we tend to use – about 30 Newtons per string – the bass strings would need to be rather thick. Could it be that we expect a higher string tension than was used in the past?

Some years ago I went on holiday to Corsica and took my six-course lute with me. Tuned in G at modern pitch, with a string length of 60cm, it was strung entirely in gut, with a string tension of about 40N for the first course (a .42mm string), about 30N for the second course, and about 28N for the rest (the sixth course was 1.40mm). When I returned home two weeks later I was astonished to find that it had gone down almost a tone in pitch, without me having noticed – there was nothing unusual in the the way it felt or sounded, in fact I was rather pleased by the quantity and quality of sound. But now the bottom string was at 23N, about 20% less than before. Of course the drop in pitch and tension had happened gradually over a period of two weeks, and I had adjusted my technique accordingly. This set me wondering about whether the string tensions which we regard as normal are higher than those which would have been used in the past.

One of the most interesting paintings of a six-course lute is the famous “Ambassadors” painting by Hans Holbein, which can be dated with some certainty to about 1533. It shows a six-course lute in exquisite detail, and there can be little doubt that the representation of the strings is reasonably accurate:

Taking measurements from paintings is always difficult, of course, but it seems to me that the sixth course is no more than about 1.25mm diameter. This is almost exactly what my lute would look like if I tuned to the usual pitch but with thinner strings to match the 20% lower tension.

So far so good, but there is a limit to how thin a gut string can be made, and modern opinion is that this is about .42mm or more. So my top string might have to stay at the higher tension, even if the rest could be lower. This violates the oft-repeated principle that strings should be of equal tension from highest to lowest, but perhaps the issue is not so much equal tension as equal “feel”. In fact with gut strings, and particularly on lutes with more courses, it is often a good idea to grade the string tension so that thicker strings are at lower tension than thin ones. This makes sense in terms of the tradeoff between tension and flexibility – with low bass strings, the advantage of the extra flexibility provided by a thinner string seems to outweigh any disadvantage of being at a lower tension.

When it comes to a later period, from about 1600 most players seem to have used a technique where they plucked the strings much closer to the bridge, and it is here where I think the biggest difference between modern practices and those of the past are to be found. Nowadays it is common practice to use metalwound strings for basses, even though there is practically no evidence for their use on lutes at any period in history. Even in the last days of the lute in the late 18th century, it is clear that wound strings were not used. In this painting by Lisiewska there is no sign of wound strings (as you would expect, given the design of the “swan-neck” lute which allows roughly the same string diameter for the 13th course as for the 8th course):

Modern metalwound strings are extremely flexible and have to be tuned at a relatively high tension otherwise they are very hard to control, a problem which is made worse by the modern tendency to play more towards the rose than the bridge. I suggest that if we use gut or synthetic strings without metal windings, use low string tensions and play close to the bridge, we can get much closer to the kind of sound and feel which would have been familiar to 17th century lutenists. This anonymous 17th century painting shows a typical hand position: